/*
 * Licensed under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.gearpump.streaming.dsl.api.functions

/**
 * Combines input into an accumulator.
 *
 * @tparam A type of accumulator
 * @tparam T Type of input
 */
abstract class FoldFunction[T, A] extends SerializableFunction {

  def init: A

  def fold(accumulator: A, t: T): A
}
